FIG. 1 shows a prior art umbrella, in which a husk (1) encloses the pivotal joint connecting a tail rib (2) to an intermediate rib (3) to form a construction of an umbrella. The husk (1) has a tail end (11) embracively engaged with the front end of the tail rib (2) to enhance the strength of an umbrella and to align the tail rib (2) and the intermediate rib (3) in an approximately straight line when the umbrella opens. However, the outer end (21) of a tail rib (2) is usually connected to an umbrella cloth. When wind is strong, the energy applied on the surface of an umbrella canopy and transmitted to ribs (as shown in FIG. 2) often breaks the husk (1) at its root (111) and the tail rib (2), which disables an umbrella.
In view of the deficiency, the primary object of the invention is to provide a tail rib structure that elongates the pivotal joint between the tail rib and the flexible rib and which encases the joint in a husk to construct an umbrella having high wind resistant strength.
Now, the structure and features of the invention are described below in detail with reference to the accompanying drawings.